The invention relates to a tool for machine working of workpieces, particularly on universal machines by lathe working. The tool has a tool holder, which is provided with a fixing element with a shank section and a gripping head thickened compared therewith, as well as a cutting insert to be fixed thereto and which has at least one blade, usually two blades, an opening for the fixing element and at least one gripping surface cooperating with the gripping head. The tool holder has a gripping device for the fixing element.
Such tools are known from DE 36 32 296 A and DE 42 14 355 A. In the case of the latter tools the fixing element comprises a clamping screw, which projects through a round hole, having a conical land, in a triangular or trapezoidal cutting insert.
Particularly in the case of universal or automatic machines for the working of very small, precision mechanical workpieces, such as the spindles of clocks and watches and the like, both the cutting inserts and the tool holders are very small. As such universal machines have linear or turret-like tool changers in which the tools are housed in very closely juxtaposed manner and such machines are normally operated continuously in three shifts and only trained personnel are provided for the monitoring of their otherwise automatic operation, a problem arises if a tool has to be replaced, e.g. because it has been damaged. In this case it is normally necessary to wait for a setter, i.e. a qualified fitter, who replaces the tool.